The prediction of fire propagation in cable tray configurations remains a challenging issue in fire safety engineering, particularly for applications in nuclear installations, where realistic fire scenarios must often be assessed with limited information on key input parameters such as cable types and material properties. The FLASH-CAT model, as defined in NUREG-7010 [1], is commonly used for this purpose due to its simplicity and low computational cost. However, its simplified formulation and global treatment of fire spread limit its applicability to complex and non-uniform fire scenarios. Originally, the FLASH-CAT model was developed as an empirical approximation based on a series of experimental tests conducted under open-atmosphere conditions. To extend its validity to under-ventilated enclosures, a modified version was later proposed, incorporating the concept of a global equivalence ratio to improve the prediction of fire propagation [2]. In the present work, a cellular automata formulation of the modified FLASH-CAT model is introduced. The cable trays are discretized into elementary cells, each representing a local portion of the cable bundle. Each cell can exist in one of three states: non-ignited, ignited, or burned. Fire propagation to non-ignited cells is governed by local interactions with neighbouring ignited cells, and the probability of propagation increases when multiple ignited cells are present nearby. The proposed model is applied to simulations of several experimental tests performed within the PRISME project, as well as to the real cable fire scenario, known as the heater bay fire event, defined in the PRISME Cable Benchmark Exercise [3]. Model predictions are compared with the benchmark reference data, with particular emphasis on the temporal evolution of the heat release rate and the sprinkler activation time. The results show that the cellular automata approach improves the representation of non-uniform fire growth while maintaining a computational cost suitable for engineering-level fire analyses. [1] NUREG/CR-7010 Cable Heat Release, Ignition, and Spread in Tray Installations During Fire, Phase 1: Horizontal Trays (2012) [2] D. Lázaro, et all, New Approach to Cable Tray Fire Modelling Through a FLASHCAT Modification, Proceedings of the Tenth International Seminar on Fire and Explosion Hazards, May (2022) Oslo, Norway [3] W. Plumecocq, et all, Common OECD/NEA FIRE and PRISME Cable Benchmark Exercise, Fire Safety Journal 139 (2023)